docs: def update_asset_ddo(self, did, ddo):
          """
          Update the ddo of a did already registered.
  
          :param did: Asset DID string
          :param ddo: DDO instance
          :return: API response (depends on implementation)
          """
          response = self.requests_session.put(f'{self.url}/{did}', data=ddo.as_text(),
                                               headers=self._headers)
          if response.status_code == 200 or response.status_code == 201:
              return json.loads(response.content)
          else:
              raise Exception(f'Unable to update DDO: {response.content}')